Cancelling Attack with Artifacts And how do you detect left click every time

How do you cancel an attack with artifacts, but still let the spell (in this case a projectile spell) do damage?

using
- cancelevent{sync=true} ~onAttack
stops damage coming from the projectile.

Attacking a mob/looking at a block causes ~onSwing not to fire, how do I make sure it fires every time I hit left click?

Thanks
Goati